Because of an increasing concern of our society toward ground water contamination, and of many such cases reported annually, regulatory authorities in several jurisdictions now require that large oil, fuel and gas tanks exceeding 500 gallons for example must have a secondary containment device to prevent leakage in case of a tank rupture or perforation. A common type of secondary containment systems used with above-grade petroleum storage tanks used on farms, construction sites or logging operations is a concrete vault such as the one described in U.S. Pat. No. 5,285,914 issued to William M. Del Zotto on Feb. 15, 1994. These concrete vaults are constructed to resist cracking with thermal expansion and retraction, physical damage due to handling or collision from automobiles or the like.
A second common method for preventing leakage from a storage tank is to install an impermeable bladder inside the tank. This type of installation is illustrated and described in U.S. Pat. No. 5,195,650 issued to Tom Leidig, on Mar. 23, 1993. The bladder is made with a flexible oil impermeable material and has sufficient strength for retaining the liquid content of the tank in case of an accident with the tank or other incidence causing the rupture of the tank.
Although regulations have been developed for large petroleum tanks, there is little or no regulation with regards to residential heating oil reservoirs of 200 gallons or less. These reservoirs are typically made of steel and are known to corrode and to eventually leak. If a leaking reservoir is installed outside a house, heating oil can leak along the foundation wall, seep into the drain tile and be carried with the drainage water around the entire house. If the leak persists over a long period, it can also seep along the well pipes and contaminate the water well if there is a water well on the property. Similarly, if the leaking reservoir is installed inside the house, the leakage can infiltrate under the basement floor and become practically impossible to clean. The fumes emanating from the underground spill could render the house unlivable, and unsaleable. Even decades after the house has been demolished, the flumes emanating from the soil prevents the lawful sale of the property without firstly effecting an in depth remediation of the soil.
This lack of regulation has caused problems for homeowners, banks and insurance companies. As one will appreciate, the problem is not just with the homeowner, who faces massive clean-up costs and a drastic reduction in property value, but with the insurance company holding the insurance policy on the property, and which normally absorb the losses. Typical clean-up costs following a spill from a leaking heating oil reservoir have been reported as being as high as hundreds of thousands of dollars. When the leak gets into the aquifers of a municipality for example, the liability could reach millions of dollars.
Oil spills are not necessarily caused by the complete rupture or perforation of a tank where a substantial portion of the reservoir is spilled on the ground. Oftentimes, a residential oil tank is overfilled and leaks from the threads of the fill or vent pipe or by the level gauge on the top part of the reservoir. Then, precipitation washes out the oil over the surface of the reservoir and entrains the leaking oil into the ground. In other circumstances, leaks will occur along the fitting on the outlet pipe of the reservoir. These leaks are normally relatively small, but are nonetheless harmful to the environment whereas thread leaks are generally not taken seriously and may persist for weeks and months before being fixed.
Despite the increasing awareness of people concerning environmentally hazardous leakages of heating oil and the high cost of soil remediation processes, it is believed that there is no system available in the prior art for installation under new and old reservoirs alike, for preventing severe and light spills from these reservoirs. The reason for this is believed to be primarily due to a lacking of a practical and monetary affordable concept as disclosed herein.